First Bridge

What are the most important parts in our bridge?

Triangles- We believe the strongest part of our bridge is our triangle truss design. The triangles will help distribute the weight and forces evenly throughout the bridge. In addition when creating our first bridge we discovered that triangles were a strong design that would help us to hold as much weight as possible.

Beams- When creating our Bridge one of our main focuses was making sure our sides would be strong. We think that by doubling up on sticks to create strong beams our Bridge will be able to hold a substantial amount of weight. We took extra precautions when making our Bridge by doubling up on popsicle sticks to make sure our sides would be strong.

What is the weakest part of our bridge?

Base- As you can see from the image our base isn't really supported by much besides the two beams on the side of our bridge. We think that as the test carries on our base will begin to weaken as more weight is put on. We hoped to make up for that by making sure our beams and triangles would be strong enough to help carry some of the weight along with our base.

What Forces will be present during our Bridge test?

Compression

As you can see from the illustration above the blue highlighted area represents the top of our Bridge which is where the compression will take place. When the weight is pulling the bridge down the top of the bridge will push together causing compression.

Tension

Tension is the opposite of compression since when tension is in place the bridge will be pulled apart rather than pushed together. The blue square represents our base where the block will sit during the test. When the weight pulls down on the bridge it will cause the bottom of the bridge to pull apart which is illustrated in the image above.

Our first bridge held an outstanding weight of 131 pounds. Just as we predicted the triangle trusses and sides were extremely strong and were able to hold a substantial amount of weight. In the end the base wasn't able to hold any more weight and the bridge ended up giving away.

Here are some pictures of the damage that caused our bridge to break. As you can see the sides completely snapped, but not before holding over 100 pounds which was impressive.

Click the video if you want to see our full Bridge test.

Second Bridge

What are the most important parts of our bridge?

Triangles- Like last time we decided to stick with the triangle truss design since it proved to be very effective in the end. This time though we made sure our triangles would be even stronger by making our triangles with two sticks instead of one as shown in the picture. The arrows point to the two popsicle sticks that make up our triangle trusses.

Beams- Last time we made sure that we doubled up on our beams to make them strong. They held together very well, but we believed that if we wanted to hold even more weight we would need to triple up which is what we did. As you can see in the photo the beams are tripled together which Weill allow our bridge to hold a lot of weight and maybe even more than last time.

What is the weakest part of our bridge?

Base- We think that since the base isn't supported by much we think that's were a potential point of weakness will be. Since we took extra percautuions when building our beams we think that may be able to hold some extra weight as the test goes on. Overall the base is the potential point of weakness in our bridge.

What forces will be present during our bridge test?

Tension

Tension is one of the forces that will be present during our bridge test. As you can see in the picture above the yellow square shows where the block that holds the weight will sit on our bridge. As the test goes on the red highlighted area is where the tension will be focused. The bottom of the bridge will begin to pull apart causing tension throughout the bridge.

Compression

The second force that will be present during our bridge project will compression. Compression is the opposite of tension since instead of the bridge pulling apart it will be pushed together. As you can see in the picture above the blue highlighted area is where the compression will be mainly focused. The bridge will push together causing compression.

What did we do differently than last time?

The time around we tried to incorporate different ideas in our bridge to hopefully hold more weight than last time. As you can see in the pictures above the first thing we did was make our triangles with two popsicle sticks instead of one. The triangles proved to be a strong shape last time so we kept the shape, but strengthened the triangles by adding extra sticks. The final thing we did differently was make our beams even stronger than last time. If you watched our first bridge video our beams breaking is what caused our bridge to fall. This time we made sure our beams would be even stronger than last time doubling up three to four times. We think by incorporating this new ideas our bridge will hold even more than last time.

Conclusion

Even though we included stronger ideas in our bridge we were only able to hold 116 pounds. The base and some of the sides gave away after the weight continued to grow. We believe that because our bridge was uneven it caused it to break. Our group has taken a lot out of this project not only about building bridges and engineering, but also we learned what it's like to work as team together to complete one job. We learned about the problems bridge builders face and the success they feel when they build a successful bridge.